Firearms typically allow a user to load the firearm with a desired ammunition. When a user desires to change the type of ammunition, the user must either discharge all rounds of the previous ammunition or remove them from the firearm.
Further, if a user loads a firearm with two types of ammunition, the user may be unable to select the desired ammunition. For example, if alternating types of ammunition are loaded into the firearm, the user has no control over the ammunition to be discharged by the firearm.
What is needed, therefore, is a firearm having a selectable double-chamber magazine.